Jeff Morriss:

	Fix for bug 1036

I looked at this today and found that in fact the PC stuff is pretty
hosed up in the SS7 dissectors.  For example, MTP3 *looks* OK here (DPC is
4-5-6):

    Routing label
        DPC (4-5-6) (394500)

but 394500 == 0x60504 == 6-5-4.  Something's not right.

I made a common PC dissector function for all the SS7 dissectors so as to
concentrate all this code in one place (something I've been wanting to do for a
while anyway) and fixed the reported problem as well as the above problem in
the attached patch.


git-svn-id: http://anonsvn.wireshark.org/wireshark/trunk@19231 f5534014-38df-0310-8fa8-9805f1628bb7

5 files changed, 117 insertions, 156 deletions

diff --git a/epan/dissectors/packet-mtp3.c b/epan/dissectors/packet-mtp3.c
index e188a48f6a..0a46270e7e 100644
--- a/epan/dissectors/packet-mtp3.c
+++ b/epan/dissectors/packet-mtp3.c
@@ -156,9 +156,6 @@ static mtp3_addr_pc_t mtp3_addr_dpc, mtp3_addr_opc;
 #define ITU_OPC_MASK               0x0FFFC000
 #define ITU_SLS_MASK               0xF0000000
 
-#define ANSI_NETWORK_MASK          0x0000FF
-#define ANSI_CLUSTER_MASK          0x00FF00
-#define ANSI_MEMBER_MASK           0xFF0000
 #define ANSI_5BIT_SLS_MASK         0x1F
 #define ANSI_8BIT_SLS_MASK         0xFF
 #define CHINESE_ITU_SLS_MASK       0xF
@@ -245,7 +242,7 @@ mtp3_pc_to_str_buf(const guint32 pc, gchar *buf, int buf_len)
       break;
     case ANSI_STANDARD:
     case CHINESE_ITU_STANDARD:
-      g_snprintf(buf, buf_len, "%u-%u-%u", (pc & ANSI_NETWORK_MASK), (pc & ANSI_CLUSTER_MASK) >> 8, (pc & ANSI_MEMBER_MASK) >> 16);
+      g_snprintf(buf, buf_len, "%u-%u-%u", (pc & ANSI_NETWORK_MASK) >> 16, (pc & ANSI_CLUSTER_MASK) >> 8, (pc & ANSI_MEMBER_MASK));
       break;
     case JAPAN_STANDARD:
       switch (japan_pc_structure) {
@@ -397,6 +394,46 @@ guint32 mtp3_pc_hash(const guint8* data) {
 	return pc;
 }
 
+/*  Common function for dissecting 3-byte (ANSI or China) PCs. */
+void
+dissect_mtp3_3byte_pc(tvbuff_t *tvb, guint offset, proto_tree *tree, gint ett_pc, int hf_pc_string, int hf_pc_network,
+		      int hf_pc_cluster, int hf_pc_member, int hf_dpc, int hf_pc)
+{
+    guint32 pc;
+    proto_item *pc_item;
+    proto_tree *pc_tree;
+    char pc_string[MAX_STRUCTURED_PC_LENGTH];
+
+    pc = tvb_get_letoh24(tvb, offset);
+    mtp3_pc_to_str_buf(pc, pc_string, sizeof(pc_string));
+
+    pc_item = proto_tree_add_string(tree, hf_pc_string, tvb, offset, ANSI_PC_LENGTH, pc_string);
+
+    /* Add alternate formats of the PC
+     * NOTE: each of these formats is shown to the user,
+     * so I think that using hidden fields in this case is OK.
+     */
+    g_snprintf(pc_string, sizeof(pc_string), "%u", pc);
+    proto_item_append_text(pc_item, " (%s)", pc_string);
+    proto_tree_add_string_hidden(tree, hf_pc_string, tvb, offset, ANSI_PC_LENGTH, pc_string);
+    g_snprintf(pc_string, sizeof(pc_string), "0x%x", pc);
+    proto_item_append_text(pc_item, " (%s)", pc_string);
+    proto_tree_add_string_hidden(tree, hf_pc_string, tvb, offset, ANSI_PC_LENGTH, pc_string);
+
+    pc_tree = proto_item_add_subtree(pc_item, ett_pc);
+
+    proto_tree_add_uint(pc_tree, hf_pc_network, tvb, offset + ANSI_NETWORK_OFFSET, ANSI_NCM_LENGTH, pc);
+    proto_tree_add_uint(pc_tree, hf_pc_cluster, tvb, offset + ANSI_CLUSTER_OFFSET, ANSI_NCM_LENGTH, pc);
+    proto_tree_add_uint(pc_tree, hf_pc_member,  tvb, offset + ANSI_MEMBER_OFFSET,  ANSI_NCM_LENGTH, pc);
+
+    /* add full integer values of DPC as hidden for filtering purposes */
+    if (hf_dpc)
+	proto_tree_add_uint_hidden(pc_tree, hf_dpc, tvb, offset, ANSI_PC_LENGTH, pc);
+    if (hf_pc)
+	proto_tree_add_uint_hidden(pc_tree, hf_pc,  tvb, offset, ANSI_PC_LENGTH, pc);
+
+}
+
 static void
 dissect_mtp3_sio(tvbuff_t *tvb, packet_info *pinfo, proto_tree *mtp3_tree)
 {
@@ -435,7 +472,7 @@ dissect_mtp3_routing_label(tvbuff_t *tvb, packet_info *pinfo, proto_tree *mtp3_t
 {
   guint32 label, dpc = 0, opc = 0;
   proto_item *label_item, *label_dpc_item, *label_opc_item;
-  proto_tree *label_tree, *label_dpc_tree, *label_opc_tree;
+  proto_tree *label_tree;
   int *hf_dpc_string;
   int *hf_opc_string;
 
@@ -479,31 +516,18 @@ dissect_mtp3_routing_label(tvbuff_t *tvb, packet_info *pinfo, proto_tree *mtp3_t
     label_item = proto_tree_add_text(mtp3_tree, tvb, ROUTING_LABEL_OFFSET, ANSI_ROUTING_LABEL_LENGTH, "Routing label");
     label_tree = proto_item_add_subtree(label_item, ett_mtp3_label);
 
-    /* create the DPC tree */
-    dpc = tvb_get_ntoh24(tvb, ANSI_DPC_OFFSET);
-    label_dpc_item = proto_tree_add_string_format(label_tree, *hf_dpc_string, tvb, ANSI_DPC_OFFSET, ANSI_PC_LENGTH, mtp3_pc_to_str(dpc), "DPC (%s) (%u)", mtp3_pc_to_str(dpc), dpc);
-    label_dpc_tree = proto_item_add_subtree(label_dpc_item, ett_mtp3_label_dpc);
-
-    proto_tree_add_uint(label_dpc_tree, hf_mtp3_dpc_member,  tvb, ANSI_DPC_OFFSET + ANSI_MEMBER_OFFSET,  ANSI_NCM_LENGTH, dpc);
-    proto_tree_add_uint(label_dpc_tree, hf_mtp3_dpc_cluster, tvb, ANSI_DPC_OFFSET + ANSI_CLUSTER_OFFSET, ANSI_NCM_LENGTH, dpc);
-    proto_tree_add_uint(label_dpc_tree, hf_mtp3_dpc_network, tvb, ANSI_DPC_OFFSET + ANSI_NETWORK_OFFSET, ANSI_NCM_LENGTH, dpc);
-
-    /* add full integer values of DPC as hidden for filtering purposes */
-    proto_tree_add_uint_hidden(label_dpc_tree, hf_mtp3_24bit_dpc, tvb, ANSI_DPC_OFFSET, ANSI_PC_LENGTH, dpc);
-    proto_tree_add_uint_hidden(label_dpc_tree, hf_mtp3_24bit_pc,  tvb, ANSI_DPC_OFFSET, ANSI_PC_LENGTH, dpc);
-
-    /* create the OPC tree */
-    opc = tvb_get_ntoh24(tvb, ANSI_OPC_OFFSET);
-    label_opc_item = proto_tree_add_string_format(label_tree, *hf_opc_string, tvb, ANSI_OPC_OFFSET, ANSI_PC_LENGTH, mtp3_pc_to_str(opc), "OPC (%s) (%u)", mtp3_pc_to_str(opc), opc);
-    label_opc_tree = proto_item_add_subtree(label_opc_item, ett_mtp3_label_opc);
 
-    proto_tree_add_uint(label_opc_tree, hf_mtp3_opc_member,  tvb, ANSI_OPC_OFFSET + ANSI_MEMBER_OFFSET,  ANSI_NCM_LENGTH, opc);
-    proto_tree_add_uint(label_opc_tree, hf_mtp3_opc_cluster, tvb, ANSI_OPC_OFFSET + ANSI_CLUSTER_OFFSET, ANSI_NCM_LENGTH, opc);
-    proto_tree_add_uint(label_opc_tree, hf_mtp3_opc_network, tvb, ANSI_OPC_OFFSET + ANSI_NETWORK_OFFSET, ANSI_NCM_LENGTH, opc);
+    /* create and fill the DPC tree */
+    dissect_mtp3_3byte_pc(tvb, ANSI_DPC_OFFSET, label_tree, ett_mtp3_label_dpc, *hf_dpc_string, hf_mtp3_dpc_network,
+			  hf_mtp3_dpc_cluster, hf_mtp3_dpc_member, hf_mtp3_24bit_dpc, hf_mtp3_24bit_pc);
+    /* Store dpc for mtp3_addr below */
+    dpc = tvb_get_letoh24(tvb, ANSI_DPC_OFFSET);
 
-    /* add full integer values of OPC as hidden for filtering purposes */
-    proto_tree_add_uint_hidden(label_opc_tree, hf_mtp3_24bit_opc, tvb, ANSI_OPC_OFFSET, ANSI_PC_LENGTH, opc);
-    proto_tree_add_uint_hidden(label_opc_tree, hf_mtp3_24bit_pc,  tvb, ANSI_OPC_OFFSET, ANSI_PC_LENGTH, opc);
+    /* create and fill the OPC tree */
+    dissect_mtp3_3byte_pc(tvb, ANSI_OPC_OFFSET, label_tree, ett_mtp3_label_opc, *hf_opc_string, hf_mtp3_opc_network,
+			  hf_mtp3_opc_cluster, hf_mtp3_opc_member, hf_mtp3_24bit_opc, hf_mtp3_24bit_pc);
+    /* Store opc for mtp3_addr below */
+    opc = tvb_get_letoh24(tvb, ANSI_OPC_OFFSET);
 
     /* SLS */
     if (mtp3_standard == ANSI_STANDARD) {
@@ -666,8 +690,8 @@ proto_register_mtp3(void)
     { &hf_mtp3_itu_pc,                { "PC",                       "mtp3.pc",                FT_UINT32, BASE_DEC,  NULL,                                   0x0,                        "", HFILL }},
     { &hf_mtp3_24bit_pc,              { "PC",                       "mtp3.pc",                FT_UINT32, BASE_DEC,  NULL,                                   ANSI_PC_MASK,               "", HFILL }},
     { &hf_mtp3_24bit_opc,             { "OPC",                      "mtp3.opc",               FT_UINT32, BASE_DEC,  NULL,                                   ANSI_PC_MASK,               "", HFILL }},
-    { &hf_mtp3_ansi_opc,              { "DPC",                      "mtp3.ansi_opc",          FT_STRING, BASE_NONE, NULL,                                   0x0,                        "", HFILL }},
-    { &hf_mtp3_chinese_opc,           { "DPC",                      "mtp3.chinese_opc",       FT_STRING, BASE_NONE, NULL,                                   0x0,                        "", HFILL }},
+    { &hf_mtp3_ansi_opc,              { "OPC",                      "mtp3.ansi_opc",          FT_STRING, BASE_NONE, NULL,                                   0x0,                        "", HFILL }},
+    { &hf_mtp3_chinese_opc,           { "OPC",                      "mtp3.chinese_opc",       FT_STRING, BASE_NONE, NULL,                                   0x0,                        "", HFILL }},
     { &hf_mtp3_opc_network,           { "OPC Network",              "mtp3.opc.network",       FT_UINT24, BASE_DEC,  NULL,                                   ANSI_NETWORK_MASK,          "", HFILL }},
     { &hf_mtp3_opc_cluster,           { "OPC Cluster",              "mtp3.opc.cluster",       FT_UINT24, BASE_DEC,  NULL,                                   ANSI_CLUSTER_MASK,          "", HFILL }},
     { &hf_mtp3_opc_member,            { "OPC Member",               "mtp3.opc.member",        FT_UINT24, BASE_DEC,  NULL,                                   ANSI_MEMBER_MASK,           "", HFILL }},
diff --git a/epan/dissectors/packet-mtp3.h b/epan/dissectors/packet-mtp3.h
index 90aaeddbd9..c990e63529 100644
--- a/epan/dissectors/packet-mtp3.h
+++ b/epan/dissectors/packet-mtp3.h
@@ -56,13 +56,13 @@ typedef struct _mtp3_tap_rec_t {
 
 #define ANSI_PC_LENGTH    3
 #define ANSI_NCM_LENGTH   1
-#define ANSI_MEMBER_OFFSET 0
-#define ANSI_CLUSTER_OFFSET 1
 #define ANSI_NETWORK_OFFSET 2
+#define ANSI_CLUSTER_OFFSET 1
+#define ANSI_MEMBER_OFFSET 0
 #define ANSI_PC_MASK      0xFFFFFF
-#define ANSI_NETWORK_MASK 0x0000FF
+#define ANSI_NETWORK_MASK 0xFF0000
 #define ANSI_CLUSTER_MASK 0x00FF00
-#define ANSI_MEMBER_MASK  0xFF0000
+#define ANSI_MEMBER_MASK  0x0000FF
 #define ANSI_PC_STRING_LENGTH 16
 
 #define JAPAN_PC_LENGTH   2
@@ -74,6 +74,19 @@ extern gchar*   mtp3_pc_to_str(const guint32 pc);
 extern gboolean mtp3_pc_structured(void);
 extern guint32  mtp3_pc_hash(const guint8* data);
 
+#ifdef __PROTO_H__
+/* epan/to_str.c includes this file, but it does not include proto.h so
+ * it doesn't know about things like proto_tree.  This function is not
+ * needed by to_str.c, so just don't prototype it there (or anywhere
+ * without proto.h).
+ */
+extern void	dissect_mtp3_3byte_pc(tvbuff_t *tvb, guint offset,
+				      proto_tree *tree, gint ett_pc,
+				      int hf_pc, int hf_pc_network,
+				      int hf_pc_cluster, int hf_pc_member,
+				      int hf_dpc, int pc);
+#endif
+
 /*
  * the following allows TAP code access to the messages
  * without having to duplicate it. With MSVC and a 
diff --git a/epan/dissectors/packet-mtp3mg.c b/epan/dissectors/packet-mtp3mg.c
index e30e60b47a..86e449b431 100644
--- a/epan/dissectors/packet-mtp3mg.c
+++ b/epan/dissectors/packet-mtp3mg.c
@@ -548,38 +548,6 @@ dissect_mtp3mg_ecm(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree,
 }
 
 static void
-dissect_mtp3mg_3byte_pc(tvbuff_t *tvb, proto_tree *tree, gint *ett_pc,
-			int *hf_pc, int *hf_pc_member, int *hf_pc_cluster,
-			int *hf_pc_network)
-{
-    guint32 apc;
-    proto_item *apc_item;
-    proto_tree *apc_tree;
-    char pc[ANSI_PC_STRING_LENGTH];
-
-    apc = tvb_get_ntoh24(tvb, 0);
-
-    g_snprintf(pc, sizeof(pc), "%d-%d-%d",
-	     (apc & ANSI_NETWORK_MASK),
-	     ((apc & ANSI_CLUSTER_MASK) >> 8),
-	     ((apc & ANSI_MEMBER_MASK) >> 16));
-
-    apc_item = proto_tree_add_string_format(tree, *hf_pc, tvb, 0,
-					    ANSI_PC_LENGTH, pc,
-					    "Affected PC (%s)", pc);
-
-    apc_tree = proto_item_add_subtree(apc_item, *ett_pc);
-
-    proto_tree_add_uint(apc_tree, *hf_pc_member, tvb,
-			ANSI_MEMBER_OFFSET, ANSI_NCM_LENGTH, apc);
-    proto_tree_add_uint(apc_tree, *hf_pc_cluster, tvb,
-			ANSI_CLUSTER_OFFSET, ANSI_NCM_LENGTH, apc);
-    proto_tree_add_uint(apc_tree, *hf_pc_network, tvb,
-			ANSI_NETWORK_OFFSET, ANSI_NCM_LENGTH, apc);
-
-}
-
-static void
 dissect_mtp3mg_fcm(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree,
 		   guint8 h1)
 {
@@ -653,11 +621,10 @@ dissect_mtp3mg_fcm(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree,
 		hf_apc_string = &hf_mtp3mg_tfc_chinese_apc;
 	    }
 
-	    dissect_mtp3mg_3byte_pc(tvb, tree, &ett_mtp3mg_fcm_apc,
-				    hf_apc_string,
-				    &hf_mtp3mg_tfc_apc_member,
-				    &hf_mtp3mg_tfc_apc_cluster,
-				    &hf_mtp3mg_tfc_apc_network);
+	    dissect_mtp3_3byte_pc(tvb, 0, tree, ett_mtp3mg_fcm_apc,
+				  *hf_apc_string, hf_mtp3mg_tfc_apc_network,
+				  hf_mtp3mg_tfc_apc_cluster,
+				  hf_mtp3mg_tfc_apc_member, 0, 0);
 
 	    proto_tree_add_item(tree, hf_mtp3mg_tfc_ansi_status, tvb,
 				ANSI_TFC_STATUS_OFFSET, ANSI_TFC_STATUS_LENGTH,
@@ -691,11 +658,11 @@ dissect_mtp3mg_tfm(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree,
     case TFM_H1_TCA:
 	if (mtp3_standard == ANSI_STANDARD)
 	{
-	    dissect_mtp3mg_3byte_pc(tvb, tree, &ett_mtp3mg_tfm_apc,
-				    &hf_mtp3mg_tfm_ansi_apc,
-				    &hf_mtp3mg_tfm_apc_member,
-				    &hf_mtp3mg_tfm_apc_cluster,
-				    &hf_mtp3mg_tfm_apc_network);
+	    dissect_mtp3_3byte_pc(tvb, 0, tree, ett_mtp3mg_tfm_apc,
+				  hf_mtp3mg_tfm_ansi_apc,
+				  hf_mtp3mg_tfm_apc_network,
+				  hf_mtp3mg_tfm_apc_cluster,
+				  hf_mtp3mg_tfm_apc_member, 0, 0);
 
 	} else if (mtp3_standard == JAPAN_STANDARD) {
 	    guint8 count, i;
@@ -744,11 +711,11 @@ dissect_mtp3mg_tfm(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree,
 		}
 	    }
 	    else if (mtp3_standard == CHINESE_ITU_STANDARD)
-		dissect_mtp3mg_3byte_pc(tvb, tree, &ett_mtp3mg_tfm_apc,
-					&hf_mtp3mg_tfm_chinese_apc,
-					&hf_mtp3mg_tfm_apc_member,
-					&hf_mtp3mg_tfm_apc_cluster,
-					&hf_mtp3mg_tfm_apc_network);
+		dissect_mtp3_3byte_pc(tvb, 0, tree, ett_mtp3mg_tfm_apc,
+				      hf_mtp3mg_tfm_chinese_apc,
+				      hf_mtp3mg_tfm_apc_network,
+				      hf_mtp3mg_tfm_apc_cluster,
+				      hf_mtp3mg_tfm_apc_member, 0, 0);
 	}
 	break;
 
@@ -775,11 +742,11 @@ dissect_mtp3mg_rsm(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree,
     case RSM_H1_RCR:
 	if (mtp3_standard == ANSI_STANDARD)
 	{
-	    dissect_mtp3mg_3byte_pc(tvb, tree, &ett_mtp3mg_rsm_apc,
-				    &hf_mtp3mg_rsm_ansi_apc,
-				    &hf_mtp3mg_rsm_apc_member,
-				    &hf_mtp3mg_rsm_apc_cluster,
-				    &hf_mtp3mg_rsm_apc_network);
+	    dissect_mtp3_3byte_pc(tvb, 0, tree, ett_mtp3mg_rsm_apc,
+				  hf_mtp3mg_rsm_ansi_apc,
+				  hf_mtp3mg_rsm_apc_network,
+				  hf_mtp3mg_rsm_apc_cluster,
+				  hf_mtp3mg_rsm_apc_member, 0, 0);
 
 	} else if (mtp3_standard == JAPAN_STANDARD) {
 	    if (h1 == RSM_H1_RST)
@@ -831,11 +798,11 @@ dissect_mtp3mg_rsm(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree,
 		    }
 		}
 		else /* CHINESE_ITU_STANDARD */
-		    dissect_mtp3mg_3byte_pc(tvb, tree, &ett_mtp3mg_rsm_apc,
-					    &hf_mtp3mg_rsm_chinese_apc,
-					    &hf_mtp3mg_rsm_apc_member,
-					    &hf_mtp3mg_rsm_apc_cluster,
-					    &hf_mtp3mg_rsm_apc_network);
+		    dissect_mtp3_3byte_pc(tvb, 0, tree, ett_mtp3mg_rsm_apc,
+					  hf_mtp3mg_rsm_chinese_apc,
+					  hf_mtp3mg_rsm_apc_network,
+					  hf_mtp3mg_rsm_apc_cluster,
+					  hf_mtp3mg_rsm_apc_member, 0, 0);
 	    } else
 		dissect_mtp3mg_unknown_message(tvb, tree);
 	}
@@ -957,11 +924,10 @@ dissect_mtp3mg_ufc(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree,
 	    else /* CHINESE_ITU_STANDARD */
 		hf_apc = &hf_mtp3mg_upu_chinese_apc;
 
-	    dissect_mtp3mg_3byte_pc(tvb, tree, &ett_mtp3mg_upu_apc,
-				    hf_apc,
-				    &hf_mtp3mg_rsm_apc_member,
-				    &hf_mtp3mg_rsm_apc_cluster,
-				    &hf_mtp3mg_rsm_apc_network);
+	    dissect_mtp3_3byte_pc(tvb, 0, tree, ett_mtp3mg_upu_apc, *hf_apc,
+				  hf_mtp3mg_rsm_apc_network,
+				  hf_mtp3mg_rsm_apc_cluster,
+				  hf_mtp3mg_rsm_apc_member, 0, 0);
 
 	    proto_tree_add_item(tree, hf_mtp3mg_upu_user, tvb,
 				ANSI_UPU_USER_OFFSET, UPU_USER_LENGTH, TRUE);
diff --git a/epan/dissectors/packet-sccp.c b/epan/dissectors/packet-sccp.c
index b793c0dcef..c01d314209 100644
--- a/epan/dissectors/packet-sccp.c
+++ b/epan/dissectors/packet-sccp.c
@@ -1043,10 +1043,6 @@ static int
 dissect_sccp_3byte_pc(tvbuff_t *tvb, proto_tree *call_tree, guint offset,
                      gboolean called)
 {
-  guint32 dpc;
-  proto_item *call_pc_item = 0;
-  proto_tree *call_pc_tree = 0;
-  char pc[ANSI_PC_STRING_LENGTH];
   int *hf_pc;
 
   if (decode_mtp3_standard == ANSI_STANDARD)
@@ -1062,34 +1058,16 @@ dissect_sccp_3byte_pc(tvbuff_t *tvb, proto_tree *call_tree, guint offset,
       hf_pc = &hf_sccp_calling_chinese_pc;
   }
 
-  /* create the DPC tree; modified from that in packet-mtp3.c */
-  dpc = tvb_get_ntoh24(tvb, offset);
-  g_snprintf(pc, sizeof(pc), "%d-%d-%d", (dpc & ANSI_NETWORK_MASK),
-				       ((dpc & ANSI_CLUSTER_MASK) >> 8),
-				       ((dpc & ANSI_MEMBER_MASK) >> 16));
-
-  call_pc_item = proto_tree_add_string_format(call_tree, *hf_pc,
-					      tvb, offset, ANSI_PC_LENGTH,
-					      pc, "PC (%s)", pc);
-
-  call_pc_tree = proto_item_add_subtree(call_pc_item,
-					  called ? ett_sccp_called_pc
-						 : ett_sccp_calling_pc);
-
-  proto_tree_add_uint(call_pc_tree, called ? hf_sccp_called_pc_member
-					   : hf_sccp_calling_pc_member,
-		      tvb, offset, ANSI_NCM_LENGTH, dpc);
-  offset += ANSI_NCM_LENGTH;
-  proto_tree_add_uint(call_pc_tree, called ? hf_sccp_called_pc_cluster
-					   : hf_sccp_calling_pc_cluster,
-		      tvb, offset, ANSI_NCM_LENGTH, dpc);
-  offset += ANSI_NCM_LENGTH;
-  proto_tree_add_uint(call_pc_tree, called ? hf_sccp_called_pc_network
-					   : hf_sccp_calling_pc_network,
-		      tvb, offset, ANSI_NCM_LENGTH, dpc);
-  offset += ANSI_NCM_LENGTH;
-
-  return(offset);
+  /* create and fill the PC tree */
+  dissect_mtp3_3byte_pc(tvb, offset, call_tree,
+			called ? ett_sccp_called_pc : ett_sccp_calling_pc,
+			*hf_pc,
+			called ? hf_sccp_called_pc_network : hf_sccp_calling_pc_network,
+			called ? hf_sccp_called_pc_cluster : hf_sccp_calling_pc_cluster,
+			called ? hf_sccp_called_pc_member  : hf_sccp_calling_pc_member,
+			0, 0);
+
+  return(offset + ANSI_PC_LENGTH);
 }
 
 /*  FUNCTION dissect_sccp_called_calling_param():
diff --git a/epan/dissectors/packet-sccpmg.c b/epan/dissectors/packet-sccpmg.c
index ed9d7aaab0..4a75b07bce 100644
--- a/epan/dissectors/packet-sccpmg.c
+++ b/epan/dissectors/packet-sccpmg.c
@@ -150,11 +150,7 @@ dissect_sccpmg_affected_ssn(tvbuff_t *tvb, proto_tree *sccpmg_tree)
 static void
 dissect_sccpmg_affected_pc(tvbuff_t *tvb, proto_tree *sccpmg_tree)
 {
-	proto_item *pc_item = 0;
-	proto_tree *pc_tree = 0;
-	guint32 dpc;
 	guint8 offset = SCCPMG_AFFECTED_PC_OFFSET;
-	char pc[ANSI_PC_STRING_LENGTH];
 
 	if (mtp3_standard == ITU_STANDARD) {
 		proto_tree_add_item(sccpmg_tree, hf_sccpmg_affected_itu_pc, tvb,
@@ -172,30 +168,14 @@ dissect_sccpmg_affected_pc(tvbuff_t *tvb, proto_tree *sccpmg_tree)
 			hf_affected_pc = &hf_sccpmg_affected_chinese_pc;
 		}
 
-		/* create the DPC tree; modified from that in packet-sccp.c */
-		dpc = tvb_get_ntoh24(tvb, offset);
-		g_snprintf(pc, sizeof(pc), "%d-%d-%d",
-			 (dpc & ANSI_NETWORK_MASK),
-			 ((dpc & ANSI_CLUSTER_MASK) >> 8),
-			 ((dpc & ANSI_MEMBER_MASK) >> 16));
-
-		pc_item = proto_tree_add_string_format(sccpmg_tree,
-						       *hf_affected_pc,
-						       tvb, offset,
-						       ANSI_PC_LENGTH, pc,
-						       "PC (%s)", pc);
-
-		pc_tree = proto_item_add_subtree(pc_item,
-						 ett_sccpmg_affected_pc);
-
-		proto_tree_add_uint(pc_tree, hf_sccpmg_affected_pc_member, tvb,
-				    offset, ANSI_NCM_LENGTH, dpc);
-		offset += ANSI_NCM_LENGTH;
-		proto_tree_add_uint(pc_tree, hf_sccpmg_affected_pc_cluster, tvb,
-				    offset, ANSI_NCM_LENGTH, dpc);
-		offset += ANSI_NCM_LENGTH;
-		proto_tree_add_uint(pc_tree, hf_sccpmg_affected_pc_network,
-				    tvb, offset, ANSI_NCM_LENGTH, dpc);
+		/* create and fill the PC tree */
+		dissect_mtp3_3byte_pc(tvb, offset, sccpmg_tree,
+				      ett_sccpmg_affected_pc, *hf_affected_pc,
+				      hf_sccpmg_affected_pc_network,
+				      hf_sccpmg_affected_pc_cluster,
+				      hf_sccpmg_affected_pc_member, 0, 0);
+
+		offset += ANSI_PC_LENGTH;
 	}
 }